A-level biology required practical membrane permeability part 2

Question 1

Step 8 Leave the tubes in the water bath for ……… minutes. …… the tubes gently once every
………. Then remove the tubes from the water bath.

Answer 1

5

shake so that the beetroots don’t stick together and reduce the rate of diffusion or just have pigment outside the membrane changing the conc gradient

min

Question 2

step 9 :Immediately pour each solution into a ……….. test tube, being careful to label the tubes
appropriately. Throw ……………………………. away.

Answer 2

clean

the beetroot discs

Question 3

step 10 how should you compare solutions

Answer 3

Compare each of your solutions with the colour standards provided. 1. Note which
standard has the same colour as each of your solutions. If the colour of the solution falls
between two of the values you can use the intermediate number. For example, if the
colour value is between 2 and 4 record the colour value 3.

Question 4

11. Alternatively a colorimeter

Answer 4

can be used to record the absorbance of light.

Question 5

12. Set up a colorimeter. Use……….. to calibrate the colorimeter to ….. absorbance.
    Measure the absorbance of each of the standards you have prepared.

Answer 5

water
0 absorbance